In this letter, a very low-profile planar horn antenna is proposed. It consists of a subwavelength aperture placed into a "Bull's Eye" concentric periodic corrugated conducting plate that produces good return losses and a narrow radiated beam. The antenna is excited by means of a waveguide whose flange has been properly mechanized in the rear part of the structure. The mechanism explaining this phenomenon is similar to the enhanced transmission observed at optical wavelengths in similar structures. In this work, the circularly corrugated structure has been scaled into the microwave frequency range and, moreover, the plane wave excitation has been replaced by a subwavelength aperture excited by a conventional closed metallic waveguide. This transforms the original focusing structure into a new concept of a very low-profile feeder with potential applications.Index Terms-Bull eye, concentric periodic corrugated plate, metamaterials, subwavelength aperture, very low-profile feeder.

No abstract

No abstract

In this letter, very low profile planar horn antenna feeders are designed and measured. Using previous results of antennas consisting of a narrow slot on a metallic plane and flanked by two grooves, a further step is given here by reducing the thickness of the prototype. A key factor in the approach is the operation in the transversal slot resonance instead of the usual longitudinal slot resonance. Moreover, by inserting a dielectric material of relative permittivity r 1, the thickness can be further reduced, maintaining and even improving the radiation features of the prototype. Reducing the metallic plate thickness has important consequences in the weight and profile of the antennas, making them easy to handle and to fit into different structures. In addition, in ranges where the wavelength is of the order of centimeters, a thick metallic plate can be a serious drawback due to mechanical restrictions. In these cases the design following the rules given in this letter can alleviate this constraint.Index Terms-Corrugated plate, subwavelength aperture, very low profile feeder.

A dual-operating-band planar horn antenna having very low profile is presented in this paper. By opening a subwavelength aperture into a corrugated conducting plate, good return losses and a narrow radiated beam in each of the two desired operating frequency bands can be measured. This behavior is very similar to that observed in optical wavelengths where enhanced transmission was measured through apertures etched in metallic corrugated plates. Here, the double-corrugated structure has been scaled into the microwave frequency range and the excitation has been done by a conventional closed metallic waveguide placed in the rear part of the structure. In this way, a new concept of a very low profile feeder is proposed with potential wireless applications.Index Terms-Double-periodic corrugated plate, dual-band, subwavelength aperture, very low profile feeder.